generic ...copy_..._user primitives

provide raw_copy_..._user() and select ARCH_HAS_RAW_COPY_USER to use those.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

2 files changed, 28 insertions, 0 deletions

diff --git a/lib/Makefile b/lib/Makefile
index 320ac46a..7d875c3 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -242,3 +242,5 @@ UBSAN_SANITIZE_ubsan.o := n
 obj-$(CONFIG_SBITMAP) += sbitmap.o
 
 obj-$(CONFIG_PARMAN) += parman.o
+
+obj-$(CONFIG_ARCH_HAS_RAW_COPY_USER) += usercopy.o
diff --git a/lib/usercopy.c b/lib/usercopy.c
new file mode 100644
index 0000000..1b6010a
--- /dev/null
+++ b/lib/usercopy.c
@@ -0,0 +1,26 @@
+#include <linux/uaccess.h>
+
+/* out-of-line parts */
+
+#ifndef INLINE_COPY_FROM_USER
+unsigned long _copy_from_user(void *to, const void __user *from, unsigned long n)
+{
+	unsigned long res = n;
+	if (likely(access_ok(VERIFY_READ, from, n)))
+		res = raw_copy_from_user(to, from, n);
+	if (unlikely(res))
+		memset(to + (n - res), 0, res);
+	return res;
+}
+EXPORT_SYMBOL(_copy_from_user);
+#endif
+
+#ifndef INLINE_COPY_TO_USER
+unsigned long _copy_to_user(void *to, const void __user *from, unsigned long n)
+{
+	if (likely(access_ok(VERIFY_WRITE, to, n)))
+		n = raw_copy_to_user(to, from, n);
+	return n;
+}
+EXPORT_SYMBOL(_copy_to_user);
+#endif